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Q: What is Pulse combustion?

Pulse combustion is a form of combustion occurring in a heat exchanger specifically designed to form a Helmholtz resonator. Pulse combustion is self-aspirating, requiring no draft assist fan to provide combustion air. This form of combustion produces more energy than a conventional power burner combustion, allowing for smaller heat exchangers (less materials) and smaller vent pipe sizes to be utilized. Pulse combustion requires no moving parts and is a self sustaining process, requiring minimal electricity.

Q: What is a water tube boiler?

Any boiler where the products of combustion flow on the outside of a tube with the heat transfer media on the inside.

Q: What is a fire tube boiler?

Any boiler where the products of combustion flow on the inside of a tube with the heat transfer media (ex. water, steam, or hot oil) on the outside. The tubes can be orientated vertically, horizontally or pitched at an angle.

Q: How do I calculate payback?

Payback calculations can be performed by evaluating the savings associated with a boiler system upgrade (incorporating the thermal efficiency gains, radiant heat loss decreasing, and electrical consumption decreasing). A payback calculation can show how long new equipment will take to pay for itself, meaning the money that would have been used to operate an old system would be used toward the cost of purchasing a new system. Simple payback is calculated as the cost of installation / yearly savings.

Q: What is the turndown of a boiler?

Turndown is the ratio of a boiler’s minimum fuel input as compared to its maximum fuel input. For example, a boiler with a maximum fuel input of 2,000,000 Btu/hr and a minimum fuel input of 400,000 Btu/hr would have turndown ratio of 5:1 (2,000,000 divided by 400,000 is 5).

Q: What is modulation?

Modulation is the ability of a boiler to adjust its firing rate based off of the temperature setpoint the boiler is trying to achieve. Fulton boilers can be built in a number of electrical configurations to accomplish modulation by operating off the controls on the boiler itself or receiving a signal from a control system or building management system. For example, a Fulton Pulse boiler with a maximum fuel input of 2,000,000 Btu/hr, would be set up to operate and any input between 400,000 Btu/hr and 2,000,000 Btu/hr.

Q: When would I use steam versus hot water or thermal fluid?

Steam carries about 1000btu/lb useful energy. Hot water and thermal fluid carry much less energy (1-100Btu/lb). Steam does not require a pump to transfer the energy. Generally, if the heating temperatures required are <200°F, then hot water can be used and if temperatures >400°F are needed then thermal fluid might be a better choice. For process temperatures between 200°F and 400°F steam is considered a viable option.

Q: When should I use high-pressure versus low-pressure steam?

The pressure of the steam is directly related to its temperature. So process temperature will require steam used to be at a specified pressure. For example, a process requirement that needs temperatures at 300°F will require steam delivered at 55 psig or higher.

Q: Why do boilers have a minimum flow requirement?

Boilers with low water volumes require a minimum flow requirement to prevent localized boiling and subsequent heat exchanger damage in a low to zero water flow situation. Minimum flow requirement varies by boiler design. Regardless if a boiler itself has a minimum flow requirement, every hydronic heating system needs to be designed to carry the energy being created away from the boiler to avoid high temperature shut down.

Q: What is a condensing boiler?

Any boiler can produce condensed flue gases, but not all boilers are designed and built to withstand the by products associated with flue gas condensation. Only boilers that have heat exchangers designed and constructed to withstand the acidic qualities of flue gas condensate should be put into systems designed with water temperatures that would cause condensing to occur. Any system with return water temperatures less than 140°F should have full condensing boilers designed into it, otherwise the boilers are subject to heat exchanger failure from flue gas corrosion. Examples of materials that cannot withstand flue gas condensate are copper and cast iron.

Q: What is flue gas condensate?

When the vapors produced from combustion in a boiler change phase from a gas to a liquid, that liquid is referred to as condensate. This phase change occurs at the dew point of the vapor, which is approximately 135°F. The temperature of the water coming into a boiler will determine whether or not the vapors of combustion will be at temperatures that are subject to condensing.